The present invention relates to a pressure proportioning regulator and to a vane machine, i.e. a vane pump or motor including this pressure proportioning regulator.
The pressure proportioning regulator valve comprises a valve housing provided with a throughgoing passage having an inlet, a return duct and an outlet duct, a valve gate in the throughgoing passage having a pressing surface acted on by pressure at the inlet and another pressing surface acted on by pressure in the outlet duct and a device for reducing the pressures while maintaining a constant pressure ratio of the pressure at the inlet to the pressure at the outlet duct, the means for reducing the pressures including a first control edge arranged on the valve gate between the inlet and the outlet duct.
This type of pressure proportioning regulator valve is generally known and is used in hydraulic circuits for control of a pressure ratio between the pressure at the inlet and the pressure at a outlet duct of the valve and/or in the channels connected with it.
The known pressure proportioning regulator valve has a one-piece valve gate which has several shoulders or steps in its diameter and one control edge. It is comparatively complicated to build and correspondingly expensive to manufacture.
The valve gate is movably guided in a throughgoing passage in the housing of the pressure proportioning regulator valve. The throughgoing passage is connected by means of a by-pass duct with the inlet and the outlet duct. Thus the positive-going pressure changes at the inlet may be regulated.
In order to smoothly regulate negative-going pressure changes, an expensive duct with additional slider elements is required in the valve housing of this type of pressure proportioning regulator valve. This increases the assembly expense and the structural volume of the pressure proportioning regulator valve in addition to the number of components. Also a duct with a comparatively large number of angular sections lead to a restriction of the flow of pressurized medium by the pressure proportioning regulator valve. This type of flow damping or restriction is undesirable in many applications, because it leads to a delay in the response properties of the pressure proportioning regulator valve.